This invention relates to an information system for motor vehicles and is more particularly concerned with the use of a microprocessor in conjunction with a tape recorder that will generate sequential prerecorded messages which are related to the distance traveled so that pertinent road information is given to the driver of a motor vehicle as he proceeds along his route to a final destination.
Previously, such systems had utilized a generally complex tape recorder, either using several tracks, or using control frequencies beyond the audio range, both of which complicated the amplifier and the tape advance mechanism required to deliver the prerecorded messages. Furthermore, these systems often required complicated reduction drives to deliver the proper signal to the complex tape recorder systems.
The prior art systems also had built-in deficiencies such as a limit on the time of the prerecorded message. Because of the brevity of the message, this often lead to a cryptic explanation as to where the driver of the motor vehicle should turn off, beware of a warning or receive general guidance, etc. Next, the tape formats of these audio-information systems do not lend themselves to formats where the data concerning the distance traveled is stored on the tape itself rather than in a memory within the calculator section of the system. Still others were inheritantly slow and sluggish which resulted in unreliable performance without a means for correcting the deliver of an early or late prerecorded message.
Practically, all of these older type of audio information systems required a number of components that were undesirably large for in the dash applications, and it was in effort to provide an audio information system with better operating capability and with a simplier and less costly circuit components as well as a simplier tape format that the present invention came about.